(a) Mass of the cork = 5 g
Density of the cork = 0.25 g/cm3
Volume of the cork = Mass / Density
Volume of the cork = 5 / 0.25
= 20 cm3
(b) Mass of the spirit = 800 g
Density of the spirit = 0.25 g/cm3
Volume of the spirit = Mass / Density
Volume of the spirit = 800 / 0.25
= 3200 cm3